updated to consistently use autogen.sh

README.md

@@ -50,16 +50,11 @@ $ make install
 $ git clone git://github.com/acplt/open62541.git
 ```
 
-# Building (autoreconf only first time)
+# Building (autogen.sh only first time)
 ```bash
 $ cd open62541
-$ autoreconf --force --install
+$ ./autogen.sh
 $ ./configure
 $ make
 $ make check
 ```
-
-### Rebuilding configure tools (only if configure.am is changed)
-```bash
-$ ./autogen.sh
-```